Stretching machine grip



F. T. COPE May 15, 1934.

m n n. WMMMHUH W M W Patented May 15, 1934 UNITED STATES PATENT OFFICE STRETCHING MACHINE GRIP poration of Ohio Application September 19, 1932, Serial No. 633,800

9 Claims.

This invention relates to stretching machine grips and is herein particularly illustrated and described as applied to grips for use in the straightening of sucker rods.

In the copending application of Arthur H. Vaughan, Serial No. 633,799, filed September 19, 1932, there is illustrated and described a machine for stretching sucker rods and thereby straightening them. The present invention, while useful in a machine made according to the Vaughan invention, is also susceptible of other uses, and only so much of the said machine as is necessary for the understanding of the present invention will be described here.

- Sucker rods such as are used in deep wells comprise a body which may be upwards of ft.

long and end portions so arranged that the rods may be screwed together. Usually one end of the rod, termed the pin end, is provided with 20 a tapered male thread and the other end, termed the box end, is provided with a corresponding female thread. A squared portion is also provided to accommodate, a wrench and the squared or wrench portion is usually connected to the body by an intermediate tapered portion. It is desirable to heat treat the sucker rods to improve their physical characteristics and the heat treatment generally results in the rods getting crooked. The machine described in the Vaughan application above referred to is for the purpose of stretching the rods while still hot and thus removing any crookedness resulting from the heat treatment. In stretching the rods, it is important that the end portion be accurately alined with the body portion.

It has been heretofore proposed to engage the sucker rods by the squared wrench portions for the purpose of stretching them. This has not proved satisfactory for two reasons;difiiculty is encountered in alining the end portions of the rod with the body; and the wrench squares on the two ends are frequently not oriented alike, due to the fact that the two ends are separately forged, and consequently it is diflicult to arrange the gripping dies in the machine so as to properly grip both ends of the rod.

I overcome these objections and insure accurate alinement of the several portions of the sucker r0 rod by dispensing entirely with engagement of the squared wrench portion and instead engaging the body, the head and the tapered intermediate portion. The grips may be used for either the pin end or the box end of the rod and they accommodate themselves to any inaccuracies or variations within the tolerances such as ordinarily expected in a drop-forging operation.

In the accompanying drawing, illustrating a present preferred form of the invention,

Figure 1 is a horizontal section illustrating a pair of the improved grips together with a portion of the stretching machine, and

Figure 2 is a like view showing the other pair of grips for simultaneously engaging the other end of the rod.

The sucker rod illustrated in Figures 1 and 2 comprises a body in the form of a long cylindrical rod R, a pin end P and a box end B. Square wrench portions W are provided just back of the two ends of the rod and these wrench portions are connected to the rod-like body R by tapered intermediate portions T. I

Figure 1 shows the grips for engaging the box end of the rod. A jaw 2 is fixed in a member 3 of the stretching machine. A companion jaw 4 is dove-tailed to a slide 5 movable through a toggle mechanism 6 so as to bring the die 4 into and out of gripping relation with the fixed die 2. The line of separation of the two jaws is indicated at 7. I have shown a double line for clarity of illustration, but in practice the jaws will be moved into contact with one another.

The recesses in the jaws 2 and 4 are identical since the line of separation is on the axis of the sucker rod. Each of the jaws is provided with a semicircular recess 8 to accommodate the body R of the sucker rod. The recess 8 is only slightly larger in diameter than the body of the rod.

It thus receives the body and alines it with the axis of the die opening. A slight clearance is provided, as shown in the drawing. This takes care of variations, within tolerances, in thediameters of individual rods. The recess 8 is flared out as indicated at 9, thereby forming a shoulder which engages the intermediate tapered or shoulder portion T of the sucker rod and limits endwise movement of the rod. The maximum diameter of the recess is indicated at 10. It is very slightly larger than the diameter of the box end B of the rod. It thus clears and does not engage in any way the squared wrench portion W. It does engage and aline the box end B with the body R.

The grips illustrated in Figure 2 are identical with those illustrated in Figure 1 and they are mounted in a like machine member 3a. Portions of the apparatus illustrated in Figure 2 have been given the same reference characters as in Figure 1 with an a sufiixed thereto. The jaws shown in Figure 2 are illustrated as engaging the pin end of the rod. The pin end has a portion P which is of the same external diameter as the box end. Figure 2 also illustrates a forging flash F which has been formed in making the pin end and which has not as yet been trimmed oif. The jaws 2a and 4a may be recessed as indicated at 11 to accommodate this flash. i

As shown in the drawing, the two sets of grips are aligned with one another when in use. In using the grips, the toggle members 6 and 6a are actuated so as to separate the jaws and a hot rod to be straightened is dropped in place. The toggle memb rs are then actuated to bring the jaws together, as shown in the drawing. In this position there is, as stated, a certain amount of clearance between the grip faces and the sucker rod body and end portions. One of the frame embers, in this case the member 3a, is moved in the direction of the arrow A so as to stretch the rod. This movement first takes up any clearance between the tapered portions T of the sucker rod and the corresponding tapered faces 9 and 9a of the gripping jaws. Such faces prevent further endwise movement of the rod relative to the dies and subsequent movement of the member 3a away from the member 3 results in stretching the rod. After the stretching operation, the tension is released, the grips are opened and the member 3a is moved back toward the member 3.

My improved grips engage the rod so as to stretch the same, but without leaving any undesirable marks thereon. At the same time they l properly align the end portions of the sucker spect to one another or not, as the grips will.

work equally well in any case. The grips accommodate themselves to the variations in size usually encountered in forging operations. They are subject to relatively little wear and the ta-.

pered. portions 9. may be redressed should coca--v sion require without enlarging the diameters of the portions 8 and 10 and th reby affecting the fit of the jaws. Until the tapered portions of the sucker rod come into. engagement with the tapered portions of the grip, the sucker. rod may.

slide freely tllough the grip. Consequently, the original length of the rods may vary considerably and still be quickly inserted in the machine and without manipulation thereof to initially space the grips in an amount corresponding to the length of the rod. These variations are all taken. upin the first movement of the grips away. from one another prior to bringing the tapered portions: of the rod into engagement with the corresponding portion of the grip.

I have illustrated and described a present preferred embodiment of the invention. It will be understood, however, that this is by way of 11-. lustration only and that it may be otherwise em-v bodied within the scope of the following claims.

I claim: 1. A grip for an object having a body, an enlarged end and an intermediate shouldered portion, comprising a gripping jaw having a recessl to engage the head and aline it with the body.

2. A grip for an object having a body, an adjacent shouldered portion, a wrench engaging portion of smaller size and an enlarged head, comprising a jaw having therein a. recess of a size adapted to receive and aline the body in the die, the recess enlarging to accommodate the shouldered portion and engage the same in such manner as to limit endwise movement of the object and then continuing in enlarged size to receive and aline the head with the body while leaving the wrench receiving portion unengaged.

3. Gripping dies for an object having a body, shouldered portions at each end, wrench engaging portions of smaller size adjacent the shouldered portions, and enlarged heads at the ends of the body, comprising jaws associated with each end of the object and having therein recesses of a size adapted to receive and aline the body in the dies, the recesses enlarging to accommodate the shouldered portions and engage the same so as to limit endwise movement of; the object: and then continuing in enlarged size to receive and aline the heads, with the body while leavingthe wrench receiving portions unengaged.

4. A gripping die for an, object having a body, an enlarged end and an intermediate tapered portion, comprising a gripping jaw having a recess of a size adapted to receive and; aline the, body in the die, the recess flaring to accommoe. date the tapered portion and engage the same so as. to limit endwise movement of the object, and a recess lying beyond the flared portion and adapted tov engage the head and aline it with the body. w

5. A gripping die for an object having abody, a head and, an intermediate shouldered portiom comprising a gripping jaw. having a. recesspof a size adapted to receive and aline the body in the die, an adjacent shoulder adapted. to. en gage the intermediate shouldered portion of; theobject and limit endwise movement thereof, and a recess lying beyond the shoulderand adapted: to engage the head and aline it with. the body.

6. A gripping die for an object having a body, a head and .an intermediate shouldered portion, comprisinga gripping jaw having. a recessv of a sizeadapted to receive and aline the body. in. the die, an adjacent shoulder adapted to engage the intermediate shouldered. portion ofthe object and limit endwise movement thereof, a rece siving beyond the shoulder and adapted; to err-- gage the head and aline it with the body, the; first mentioned recess. being slightly larger'than the body so asto snugly surround the same yet to permit of accommodating rods varying slight 1y from one another in diameter.

'7. A gripping diefor an object having a. body, a head and an intermediate shouldered portion, comprising a gripping jaw having a recess of a size adapted to receive and aline the body in the die, an adjacent shoulder adapted to engage the intermediate shouldered portionof the object and limit, endwise movement thereof,, a recess. lying beyond the shoulder and adapted to engage the head and aline it with the body, the last mentioned recess being slightly larger than" the head so as to snugly surround the same yetflto permit of accommodating rods whoseheads vary slightly in size from one another.

8. A gripping die for-an object having a body, ahead and an intermediate shoulderedportion, comprising-a gripping jaw having'a recess of a size adapted to receive and aline the bo'dyin the die, an adjacent shoulder adapted to engage the intermediate shouldered portion of the object and limit endwise movement thereof, a recess lying beyond the shoulder and adapted to engage the head and aline it with the body, the first mentioned recess being slightly larger than the body so as to snugly surround the same yet to permit of accommodating rods varying slightly from one another in diameter, and the other recess being slightly larger than the head so as to snugly surround the same yet to permit of accommodating rods whose heads vary slightly in size from one another. 

